The present invention disclosed herein relates to an apparatus for detecting bio materials and a method for detecting bio materials by using the apparatus, and more particularly, to an apparatus and method for detecting bio materials by measuring surface absorbance variations of gold nanoparticles.
Biosensors are used to detect an optical or electric signal varying according to selective reaction and binding between an analysis-target assay and a biological receptor capable of recognizing a specific bio material. That is, biosensors are used to determine the existence of a bio material or analyze a bio material qualitatively or quantitatively. Materials such as enzymes, antibodies, and DNAs that can selectively react or couple with specific materials are used as biological receptors (i.e., sensing materials). Various physicochemical methods, such as a method of detecting an electric signal varying according to the existence of an assay and a method of detecting an optical signal varying according to a chemical reaction between a receptor and an assay, are used as signal detection methods for detecting and analyzing bio materials.
In a typical bio material detection method (label detection method), a specific antibody is labeled with a material such as a radioisotope or a fluorescent material, and then a corresponding antigen is quantitatively detected by measuring variations of radiation or fluorescence caused by a reaction between the specific antibody and the corresponding antigen. However, such a bio material detection method requires complicated processes and high process costs due to, for example, an additional process necessary for labeling a specific antibody with a fluorescent material emitting a specific color.
Therefore, recent research has been conducted on a label-free detection method that does not use a label material such as a fluorescent material emitting a specific color. That is, much research has been conducted on optical biosensors such as a surface plasmon biosensor, a total internal reflection ellipsometry biosensor, and an optical waveguide biosensor.
Generally, such label-free optical biosensors using surface plasmon, total internal reflection, or an optical waveguide are configured by an optical source unit capable of emitting light, a reacting unit adapted for reacting antibodies and antigens, and an optical detecting unit adapted for detecting an optical signal. Generally, a device such as a light-emitting diode and a laser is used as the optical source unit, and a spectrometer is used as the optical detecting unit.
However, in the case of using a spectrometer as the optical detecting unit, the sensitivity of the optical detecting unit may vary largely according to the direction of light incident on the reacting unit. Furthermore, to measure an optical spectrum, the optical source unit should be a frequency variable optical source unit, or the optical detecting unit used to detect variations of an optical signal should be a spectrometer. Therefore, very complicated optical systems are required for configuring the optical source unit and the optical detecting unit, and thus the manufacturing costs of a biosensor increase.